The Red Menace (The Shadow #7)

Some old friends return, and an old acquaintance from Russia, in Prince Zukor. Along with Bruce Duncan, the recipient of some jewels in an earlier book from the aforementioned czarist. Harry Vincent encounters an of course conflicted babe in that not very salubrious den of iniquity, The Pink Rat. There is a game of plot and counter-plot between The Shadow and the Red Envoy, with Duncan, Vincent, and Vic Marquette caught in the middle. A nasty sojourn on Death Islands awaits a couple of these worthies, with the mysterious Professor Whitburn. This one definitely keeps you guessing, until the end.